Chapter 10 Flashcards
*Which of the following is true of Multiprotocol Label Switching? (Select two.)
- CEF is required for all MPLS-enabled Cisco routers.
- MPLS-enabled routers switch packets based on the packet contents, not on label information.
- MPLS can carry ATM, SONET, and Ethernet traffic.
- Packets routed using MPLS require additional routing lookup overhead.
- MPLS is designed to forward only packets created with the TCP/IP protocol.
- CEF is required for all MPLS-enabled Cisco routers
- MPLS can carry ATM, SONET, and Ethernet traffic.
Key facts about Multiprotocol Label Switching (MPLS) include the following:
- MPLS can carry ATM, SONET, and Ethernet traffic.
- CEF is required for all MPLS-enabled Cisco routers.
- Packets are routed with a minimal amount of routing lookup overhead.
- MPLS-enabled routers switch packets based on the label information, not on the packet contents.
- MPLS is designed to support forwarding of protocols other than TCP/IP.
*When implementing a Multiprotocol Label Switching (MPLS) WAN, which data unit is managed by the routers at different sites?
- Frames
- Packets
- Datagrams
- Bits
-Packets
In a Multiprotocol Label Switching (MPLS) WAN, IP packets are forwarded between sites. Packets are forwarded based on the contents of the label, without examination of the packet. This allows the creation of end-to-end circuits across any type of WAN transport medium using any protocol.
Which VSAT component provides data transmission capabilities over a satellite link?
- Indoor unit (IDU)
- Block Upconverter (BUC)
- Orthomode transducer (OMT)
- Low-noise Block Downconverter (LNB)
-Block Upconverter (BUC)
A VSAT implementation consists of the following components:
- Block Upconverter (BUC) for transmitting data.
- Antenna.
- Low-noise Block Downconverter (LNB) for receiving data.
- Orthomode transducer (OMT) to combine and/or separate two microwave signals.
- Interfacility link cable (IFL).
- Indoor unit (IDU) to provide an interface to the organization’s network using two physical connections:
- One Ethernet port that provides an interface for the organization’s internal router.
- Two F-type connectors that connect to the BUC and the LNB on the dish.
Which of the following describe the channels and data transfer rates used for ISDN BRI? (Select two.)
- Two channels operating at 64 Kbps each
- 23 channels operating at 64 Kbps each
- One channel operating at 16 Kbps
- One channel operating at 64 Kbps
- 11 channels operating at 64 Kbps
Two channels operating at 64 Kbps each
One channel operating at 16 Kbps
ISDN BRI uses two channels operating at 64 Kbps and one channel operating at 16 Kbps. It is often called 2B + 1D
*Which of the following services are available regardless of whether the telephone company network is available?
- ISDN
- DSL
- Cable modem
- Dial-up
-Cable modem
EXPLANATION
A cable modem is a network connectivity service provided by the cable television service provider. Cable modem operates by adding a bi-directional channel connected directly to an internet service provider through cable TV lines. It does not depend on phone lines for the connection.
*Which WAN connection types use digital communications over POTS? (Select two.)
- SONET
- X.25
- ISDN
- 56 Kbps dialup
- ATM
- DSL
- ISDN
- DSL
EXPLANATION
Both DSL (Digital Subscriber Line) and ISDN (Integrated Services Digital Network) use regular phone lines (POTS) for digital communications.
56 Kbps dial-up uses analog signals over regular phone lines. X.25 can use either digital or analog signaling, but uses analog signaling when implemented over standard telephone lines. SONET operates over fiber optic cables. ATM uses fixed-length cells for transmitting data over a variety of media (twisted pair and fiber optic being the most common).
*Match each WAN topology to its description. Each topology will only be used once.
A) Connects multiple network locations to each other via WAN links. Each location has a direct link to all other locations.
B) A single, pre-established path from one network location, through a carrier network, and to a remote network location.
C) Connects multiple remote networks via WAN links. One site is the main location.
D) Provides two separate physical connects to a single ISP.
E) A network connected to an ISP using a single line.
- Hub and spoke
- Full mesh
- Single-homed
- Point-to-point
- Dual-homed
A/2
B/4
C/1
D/5
E/3
Which switching network type allows data connections that can be initiated when needed and terminated when communication is complete?
- Hub and spoke
- Packet
- Circuit
- Point-to-point
Circuit
A circuit switching network allows data connections that can be initiated when needed and terminated when communication is complete. It works much like a telephone line works for voice communication. A circuit switched network uses a dedicated connection between sites. It is ideal for transmitting data that must arrive quickly and in the order it is sent, as is the case with real-time audio and video.
*Which of the following is an example of a public WAN?
Cable internet
Leased lines
MPLS
ISDN
Cable internet
A public WAN (such as the internet) allows access to any number of sites outside the private network. The communication lines are not protected, and the entity initiating the communication is responsible for the security of the data. Public WAN connections can include:
Cable internet
Public Switched Telephone Network (PSTN), which uses the internet
ISDN, which uses the internet
Cellular
DSL
A private WAN allows a site to connect to one or more designated sites using communication methods that maintain the privacy of the data being transferred. Private WANs typically use the following types of WAN technologies to connect sites:
Integrated Services Digital Network (ISDN)
Leased lines
Ethernet WANs
Multiprotocol Label Switching (MPLS)
Very Small Aperture Terminal (VSAT)
Which cellular network type can, theoretically, provide speeds up to 10Gbps?
- 5G
- 2G
- 3G
- 4G
-5G
5G offers speeds up to 10Gbps. 5G cellular networks is the latest standard. It is now available, and coverage is expanding.
2G (second generation) networks were the first to offer digital data services. 2G data speeds are slow (14.4 Kbps) and are used mainly for text messaging, not internet connectivity.
3G offers simultaneous voice and data. Minimum speeds for stationary users are quoted at 2 Mbps or higher.
4G is available with minimum speeds around 3 Mbps, with over 100 Mbps possible.
*Which is the default Layer 2 encapsulation method for serial interfaces on a Cisco router?
- Ethernet
- HDLC
- PPP
- Frame Relay
HDLC
The High-Level Data Link Control (HDLC) WAN protocol is the default encapsulation method configured on Cisco serial interfaces.
Point-to-Point (PPP) and Frame Relay are two other common WAN encapsulation methods used on synchronous serial connections, but neither of them are the default. Ethernet is a LAN protocol and cannot be configured on serial interfaces.
*Drag each leased line component on the left with its corresponding description on the right. Each component may be used once, more than once, or not at all.
- Connects the WIC in the router to the telecom equipment.
- Controls the speed and timing of the router’s serial interfaces.
- Provides the clocking function on the link.
- The equipment at the customer site.
- Provides a Layer 1 interface between the router and the telecom provider’s equipment.
Serial cable
CPE
CSU/DSU
Connects the WIC in the router to the telecom equipment.
Serial cable
Controls the speed and timing of the router’s serial interfaces.
CSU/DSU
Provides the clocking function on the link.
CSU/DSU
The equipment at the customer site.
CPE
Provides a Layer 1 interface between the router and the telecom provider’s equipment.
CSU/DSU
Which of the following is true regarding WAN leased lines?
- The speed is symmetric.
- Provides a data-link layer transmission facility.
- Each router runs in half-duplex.
- Each router runs in full-duplex.
- The speed is asymmetric.
- The speed is symmetric.
- Each router runs in full-duplex.
The following are facts about WAN leased lines.
- Each router runs in full-duplex.
- The speed is symmetric, meaning that both routers send bits at the same speed.
- The lease line provides a physical layer bit transmission facility:
- Routers require a data link protocol on the WAN link.
- The lease line itself does not define a Data Link layer protocol to be used.
*What is the removable card that contains the serial interface on a router called?
- CPE
- CSU
- WIC
- HDLC
WIC
Serial interfaces on the router are typically a removable card called a WAN interface card (WIC).
The CSU is a device that provides the clocking function. This function physically controls the speed and timing that the router’s serial interfaces use to send and receive bits over the serial cable.
The CPE is the equipment at the customer site.
HDLC is often used as the data link protocol for WAN leased line connections.
*Which of the following is a type of line supported by a leased line?
- T1
- T5
- T4
- T2
- T3
T1
T3
*You are configuring a serial connection and need to configure the DCE to provide a clocking signal.
Given that you have leased a 128 Kbps line from the WAN service provider, which command should you use to accomplish this task?
-clock rate 128
-clock rate 128000
-clock 128000
-encapsulation hdlc 128
clock rate 128000
The clock rate command sets the clock rate on the DCE serial interface. When you issue this command, you need to specify the clock speed to use in bits per second. Because a 128-Kbps link has been leased from the WAN service provider, the speed of the link should be set to approximately 128000 bps.
*You have a small network as shown. Router2 is connected to the internet through a fiber optic FastEthernet connection and will be configured with NAT to provide internet connectivity to your private network.
What type of address would you assign to the Fa0/1 interface on Router2?
- Inside global
- Outside global
- Outside local
- Inside local
Outside global
The interface that connects the NAT router to the internet is assigned an outside global IP address. This is a public IP address that is registered and recognized on the internet.
*You have a small network connected to the internet as shown.
Which of the following statements is true? (Select two.)
- Internet hosts can reach Srv2 without NAT.
- Internet hosts can reach Srv1 without NAT.
- The router must be configured for NAT for Srv2 to communicate on the internet.
- The router must be configured for NAT for Srv1 to communicate on the internet.
- The router must be configured on all interfaces with NAT.
- Internet hosts can reach Srv2 without NAT.
- The router must be configured for NAT for Srv1 to communicate on the internet.
The subnet connected to Fa0/0 is using private IP addressing; therefore, NAT must be configured before Srv1 can communicate on the internet. The subnet connected to Fa0/1 is using public addressing; therefore, NAT is not required.
*You have a small business network with a single subnet connected to the internet through a Cisco router (RouterA). IP addresses are assigned as shown.
A browser session on the workstation tries to connect to the www.westsim.com web server.
What IP address and port number will the web server use as the destination address when responding to the workstation’s request?
- IP address 199.67.111.89 and a dynamic port chosen by the web server
- IP address 199.67.111.89 and a dynamic port assigned by RouterA
- IP address 172.17.1.1 and port 80
- IP address 199.67.111.89 and port 80
- IP address 172.17.1.55 and a port chosen by Wrk1
- IP address 172.17.1.55 and port 80
IP address 199.67.111.89 and a dynamic port assigned by RouterA
When the outgoing request passes through RouterA, the router translates the private inside IP address into a public address and a port number. The public address it uses in this case is its own public IP address (199.67.111.89). To identify the private host, it generates a random port number and associates that number with the private IP address. The outgoing packet identifies 199.67.111.89 with the random port number as the source address, so the web server uses this address when responding to the request.
*You have an office network connected to the internet as shown. The network has three subnets, all with client computers.
The Web1 server on Subnet1 hosts a small website used for traveling employees. Employees must be able to contact the web server from the internet. All other hosts on the private network need to have full internet connectivity for browsing the web and sending email.
On which routers should you configure NAT?
- RouterA and RouterC
- RouterC
- RouterA
- RouterB
- RouterA, RouterB, and RouterC
-RouterC
Configure NAT only on RouterC. RouterC can provide network address translation for all hosts on the private network, even across multiple subnets. To allow internet hosts to contact the Web1 server, obtain a public IP address for the web server and create a static NAT mapping. Alternatively, you can create a port mapping to redirect messages sent to the public address of RouterC and port of 80 to the Web1 server.
*You want to configure static NAT so that packets from host 192.168.2.100 will always be assigned the registered IP address 24.1.2.11 as shown. Match the missing lines with the required commands.
Router(config)#
- ip nat inside source static 192.168.2.100 24.1.2.11
- ip nat inside source static 192.168.2.1 24.1.2.8
- ip nat pool net-1 24.1.2.8 24.1.2.11
- ip nat inside
- ip nat outside
Router(config)# interface ethernet 0
Router(config-if)#
- ip nat inside source static 192.168.2.100 24.1.2.11
- ip nat inside source static 192.168.2.1 24.1.2.8
- ip nat pool net-1 24.1.2.8 24.1.2.11
- ip nat inside
- ip nat outside
Router(config-if)# interface serial 0
Router(config-if)#
Router(config)#
- ip nat inside source static 192.168.2.100 24.1.2.11
Router(config)# interface ethernet 0
Router(config-if)#
- ip nat inside
Router(config-if)# interface serial 0
Router(config-if)#
- ip nat outside
To meet the requirements of this scenario, you must use Static translation. Static translation consistently maps an unregistered IP address to a registered IP address on a one-to-one basis, whereas using a pool of addresses might assign a different registered IP address each time. Properly configuring the NAT router for this scenario requires three steps:
- From global configuration mode, create a mapping for the inside (private) address to the outside (public) address with the command ip net inside source static 192.168.2.100 24.1.2.11.
- Identify the E0 interface as the inside (private or unregistered) network interface with the command ip nat inside.
- Identify the S0 interface as the outside (public or registered) network interface with the command ip nat outside.
The command ip nat inside source static 192.168.2.1 24.1.2.8 maps the address of the default gateway, not the host, which is incorrect.
The command ip nat pool net-1 24.1.2.8 24.1.2.11 establishes an address pool of four registered IP addresses ranging from 24.1.2.8 to 24.1.2.11 inclusive. Unfortunately, dynamic translation (an address pool) will not work for this scenario because it maps an unregistered IP address to any available IP address configured in the pool.
You want to configure NAT so that packets from all hosts on network 192.168.2.0 will share the registered IP address 24.1.2.8 as shown. You have already identified the inside and outside NAT interfaces on the router. Which of the following command options will translate all inside host addresses to the single registered IP address?
- *-access-list 1 permit 192.168.2.0 0.0.0.255**
- *ip nat inside source list 1 interface serial 0 overload**
-ip nat pool 24.1.2.8 24.1.2.11
-ip nat pool 192.168.2.0 192.168.2.255
-ip nat inside source static 192.168.2.0 24.1.2.8
- *-access-list 1 permit 192.168.2.0 0.0.0.255**
- *ip nat inside source list 1 interface serial 0 overload**
